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// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: 2022 The Ebitengine Authors
//go:build (darwin || freebsd || linux) && !android && !faketime
package purego
import (
"unsafe"
)
// Unix Specification for dlfcn.h: https://pubs.opengroup.org/onlinepubs/7908799/xsh/dlfcn.h.html
var (
fnDlopen func(path string, mode int) uintptr
fnDlsym func(handle uintptr, name string) uintptr
fnDlerror func() string
fnDlclose func(handle uintptr) bool
)
func init() {
RegisterFunc(&fnDlopen, dlopenABI0)
RegisterFunc(&fnDlsym, dlsymABI0)
RegisterFunc(&fnDlerror, dlerrorABI0)
RegisterFunc(&fnDlclose, dlcloseABI0)
}
// Dlopen examines the dynamic library or bundle file specified by path. If the file is compatible
// with the current process and has not already been loaded into the
// current process, it is loaded and linked. After being linked, if it contains
// any initializer functions, they are called, before Dlopen
// returns. It returns a handle that can be used with Dlsym and Dlclose.
// A second call to Dlopen with the same path will return the same handle, but the internal
// reference count for the handle will be incremented. Therefore, all
// Dlopen calls should be balanced with a Dlclose call.
//
// This function is not available on Windows.
// Use [golang.org/x/sys/windows.LoadLibrary], [golang.org/x/sys/windows.LoadLibraryEx],
// [golang.org/x/sys/windows.NewLazyDLL], or [golang.org/x/sys/windows.NewLazySystemDLL] for Windows instead.
func Dlopen(path string, mode int) (uintptr, error) {
u := fnDlopen(path, mode)
if u == 0 {
return 0, Dlerror{fnDlerror()}
}
return u, nil
}
// Dlsym takes a "handle" of a dynamic library returned by Dlopen and the symbol name.
// It returns the address where that symbol is loaded into memory. If the symbol is not found,
// in the specified library or any of the libraries that were automatically loaded by Dlopen
// when that library was loaded, Dlsym returns zero.
//
// This function is not available on Windows.
// Use [golang.org/x/sys/windows.GetProcAddress] for Windows instead.
func Dlsym(handle uintptr, name string) (uintptr, error) {
u := fnDlsym(handle, name)
if u == 0 {
return 0, Dlerror{fnDlerror()}
}
return u, nil
}
// Dlclose decrements the reference count on the dynamic library handle.
// If the reference count drops to zero and no other loaded libraries
// use symbols in it, then the dynamic library is unloaded.
//
// This function is not available on Windows.
// Use [golang.org/x/sys/windows.FreeLibrary] for Windows instead.
func Dlclose(handle uintptr) error {
if fnDlclose(handle) {
return Dlerror{fnDlerror()}
}
return nil
}
func loadSymbol(handle uintptr, name string) (uintptr, error) {
return Dlsym(handle, name)
}
// these functions exist in dlfcn_stubs.s and are calling C functions linked to in dlfcn_GOOS.go
// the indirection is necessary because a function is actually a pointer to the pointer to the code.
// sadly, I do not know of anyway to remove the assembly stubs entirely because //go:linkname doesn't
// appear to work if you link directly to the C function on darwin arm64.
//go:linkname dlopen dlopen
var dlopen uint8
var dlopenABI0 = uintptr(unsafe.Pointer(&dlopen))
//go:linkname dlsym dlsym
var dlsym uint8
var dlsymABI0 = uintptr(unsafe.Pointer(&dlsym))
//go:linkname dlclose dlclose
var dlclose uint8
var dlcloseABI0 = uintptr(unsafe.Pointer(&dlclose))
//go:linkname dlerror dlerror
var dlerror uint8
var dlerrorABI0 = uintptr(unsafe.Pointer(&dlerror))
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